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Flashcards in Carbohydrates 3 Deck (29)
1

How many molecules of G-3-P enter the payoff phase?

2

2

How many ATP are used in the prepatory phase?

2

3

How many ATP are made during the payoff phase?

4

4

What is the first reaction of glycolysis?

Phosphorylation of glucose

5

How many ATP is used during the first stage of glycolysis? (phosphorylation of glucose) And what enzyme is used?

1 ATP
Hexokinase

6

What is the second stage of glycolysis? And what is the enzyme?

Conversion of G - 6 - P to F-6-P
Phosphohexose Isomerase

7

Why does the second step of glycolysis proceed in both directions?

Reaction has a low free energy

8

What is the stage of glycolysis apart from step 1 (phosphorylation of glucose) that requires ATP?

Phosphorylation of F-6-P to F-1,6 - bisP (stage 3)

9

What is the catalyst for phosphorylation of F-6-P?

Phosphofructokinase -1

10

What is the splitting part of Glycolysis?

Step 4 - which is the cleavage F-1, 6-bisP, forms two different triose sugars
Catalyst is aldolase

11

What is stage 5 of glycolysis?

Interconversion of triose sugars
Enzyme used it triose phosphate isomerase
Dihydroxyacetone phosphate is converted to glyceraldehyde -3-phosphate
Forming 2 molecules of G-3-P
G-3-P is the only molecule that can enter the payoff phase

12

Which stage in glycolysis produces 2 molecules of NADH?

Stage 6, the oxidation of G-3-P to 1,3-bisPG

The catalyst is glyceraldehyde - 3 - phosphate dehydrogenase

The first payoff reaction in glycolysis

13

Reaction 6 (the oxidation of G-3-P to 1,3-bisPG) is coupled to which other reaction and why?

6 is coupled to 7 because 6 requires a lot of energy whilst 7 gives off a a lot of energy.

14

Describe reaction 7 and what is the substrate?

P transfer from 1,3-bisPhosphoglycerate to ADP, 2 ATP produced, phosphoglycerate kinase enzyme used
Spontaneous since highly exergonic

15

What is stage 8?

Conversion of 3, phosphoglycerate to 2, phosphoglycerate
Enzyme is phosphoglycerate mutase

16

What step of glycolysis is enolase used in?

Dehydration 2-PG to PEP (phosphoenolpyruvate)

17

Where does the ADP in the last stage of glycolysis get the phosphate?

PEP

18

Describe the last stage of glycolysis

Transfer of P from PEP to ADP
2 ATP produced, highly exergonic,
Pyruvate produced
Enzyme is pyruvate kinase

19

Where does NAD+ come from in the cell?

Niacin an essential vitamin

20

What is the difference between substrate level phosphorylation and respiration linked phosphorylation ?

Substrate level - requires soluble enzymes and chemical intermediates
Respiration linked means membrane bound enzymes and gradients of protons

21

What compound is used to replenish NAD+?

The different fates of pyruvate

22

What is NAD+ used for?

The reduction of various intermediate metabolites

23

What are the three fates of pyruvate?

Citric acid cycle, producing water and carbon dioxide
Fermentation to lactate
Fermentation to CO2 and Ethanol

24

How is pyruvate converted into ethanol?

Pyruvate + pyruvate carboxylase = Acetaldehyde
Acetaldehyde + Alcohol dehydrogenase + NADH = Ethanol + NAD+

25

Why can't we make ATP via oxidative phosphorylation during intense exercise?

Not enough oxygen

26

How is ATP made instead during intense exercise?

Substrate level phosphorylation producing lactate

27

Where is the lactate converted into glucose, and what is this process called?

Liver, gluconeogenesis

28

What is the interaction between the muscle and the liver called?

The cori cycle

29

What is pyruvate converted into in aerobic conditions?

Acetyl Co-A, in mitochindria, NADH is formed